Reef Mens Rover Sandal/Flip Flops/Slipper Footwear, Black/Red, Size 11 Synthetic nubuck upper Comfort: Super soft contoured foam footbed for instant comfort Support: Medium density molded foam midsole for long-lasting support Reef Rover Sandal/Flip Flops/Slipper Footwear for Men Water friendly synthetic nubuck upper Synthetic nubuck upper. Rubber outsole